Microvalves of the kind mentioned above are known. For example, reference is made to the patent application laid open DE 102 27 593 A1, the U.S. Pat. No. 6,748,975 B2 and the article “10-Way micro switching valve chip for multi-directional flow control”, Tadahiro Hasegawa et al, 7th International Conference on Miniaturized Chemical and Biochemical Analysis Systems, 5-9 Oct. 2003, Squaw Valley, Calif. USA.
From DE 102 27 593 A1, for example, there is known a microvalve, which has a substrate and a cover plate as valve body, which have contact surfaces lying against each other in fluid-tight contact and can be positioned relative to each other so that fluid lines can be optionally connected or separated. The microvalve is disclosed as being either a rotary valve with a cylindrical cover plate or a slide valve with a rectangular cover plate. Polymer materials and optionally composite materials are proposed preferably as the substrate and cover plate material.
The present invention deals with the question of how to create a simple and functionally reliable connection of the valve body and the sealing element to the substrate, as in such microvalves. Since the aforementioned microfluidics systems and especially the lab-on-a-chip systems are generally designed for onetime use, a low-cost solution is desirable. DE 102 27 593 A1 offers no clues for this.
In U.S. Pat. No. 6,748,975 B2 is disclosed a rotary valve, which is formed by a valve body (or rotor) which can turn relative to the substrate (or stator). The rotor can turn between two or more valve positions, in which one or more channels in the rotor optionally connects one or more inlet openings with one or more outlet openings, or separates these. The rotor lies by one contact surface on a corresponding contact surface of the stator. The position of the rotor with respect to the stator is defined by inserting the two elements in a valve housing, which besides the rotor and the stator includes various means for pressing on and activating the valve. Even though the rotor and the stator are loose parts in this case and seem suitable for onetime use, still a considerable expense is required to assembly the functional valve and thus the manipulation of the valve become more difficult.
A rotary valve consisting of a substrate and a rotating valve body is also pointed out in the aforementioned article by Hasegawa et al., which lie against each other by their contact surfaces. The valve body is formed from a silicone rubber ring with channels worked into it, which is pressed against the substrate by means of a mechanism consisting of at least four parts, including a pressing spring. Just how the pressing spring is buttressed against the substrate is not evident from the article. Here as well, it is to be assumed that an enclosing valve housing is provided, which receives the valve arrangement.
The inventor itself has already presented microvalve arrangements with a substrate 210 and a valve body 212 of the aforementioned kind at the conference “MipTec—The 9th International Conference and Exhibition on Drug Discovery” on 9 May 2006, as described hereafter by means of FIG. 1. The valve body 212 is in the form of an elastomer seal and is pressed by its contact or sealing surface 214 against a corresponding contact or sealing surface 216 of the substrate 210 via a valve cylinder 218. The valve cylinder 218 is fashioned in the form of a plunger and has a pressing force applied to it by means of a compression spring 220. The compression spring 220 in turn thrusts against a housing 222, which is screwed directly onto the substrate 210 by means of a screw connection 224. The microvalve arrangement of FIG. 1 is of simple construction when compared to the aforesaid prior art, yet still a multitude of different materials and components are needed and the onetime assembly is still too elaborate in practice for a mass production.